Modelling of geothermal resources within abandoned coal mines, Upper Silesia, Poland

Abstract

The geothermal power potential of abandoned, water filled coal mines in the Upper Silesia region was estimated by numerical modelling. The heat exchange between 20°-40°C warm water filling the typical mine and the surrounding rocks was simulated using the TOUGH code and program HEAT MINE developed specifically for this project. Sensitivity analysis shows that the geometry and depth of the mine as well as the thermal properties and permeability of surrounding rocks have a large influence on the thermal power obtained from the mine. Predictions of temperature fall in the mine reservoir in response to heat extraction at the surface were made assuming a total mine volume of 1,000,000 m3 and an average radius of mine openings of 0.5 m. The predictions shows that it is possible to extract heat at a rate of about 20 MWt from the whole mine with temperature fall of 7-8°C over a period of 50 years. The modelling indicates that a large amount of geothermal energy may be obtained from the coal mines of Upper Silesa in economical and environmentally friendly way.